Thursday, June 30, 2011

6/30/11: Thursday's Weather Report

Issued at 3:50 PM CDT, Thursday, June 30th, 2011

*HEAT ADVISORY*
Source:  NWS Duluth, MN.

Heat Advisory is in effect until 9 PM CDT This Evening for the following counties.  In Minnesota:  Koochiching...Itasca...Cass...Crow Wing...and Aitkin.  Some cities included in the advisory:  International Falls MN...Littlefork MN...Bigfork MN...Grand Rapids MN...Cass Lake MN...Walker MN...Leader MN...Brainerd MN...Aitkin MN...Hill City MN...and McGregor MN.

*High temperatures in the 80s to lower 90s combined with dewpoints in the lower 70s will produce heat index values of 95 to 100 degrees into early This Evening.

*These hot and humid conditions will potentially produce a heightened risk of heat related stress and illness.

A heat advisory means that a period of hot temperatures is expected.  The combination of hot temperatures and high humidity will combine to create a situation in which illnesses are possible.  Drink plenty of fluids...Stay in air-conditioned room...Stay out of the sun...and check up on relatives and neighbors.

*HEAT ADVISORY*
Source:  NWS Duluth, MN.

Heat Advisory is in effect until 9 PM CDT This Evening and from 12 PM CDT until 9 PM CDT Friday for Pine county in Eastern Minnesota.  Some cities included in the advisory are:  Pine City MN...and Hinckley MN.

*Temperatures in the lower 90s through early This Evening and again Friday Afternoon and early Evening combined with dewpoints in the lower 70s will produce heat index values ranging from 95 to 100 degrees.

*HEAT ADVISORY*
Source:  NWS Duluth, MN.

Heat Advisory is in effect from 12 PM CDT Friday until 9 PM CDT Friday for the following counties in Northwest Wisconsin:  Douglas...Bayfield...Ashland...Iron...Burnett...Washburn...Sawyer...and Price.  Some cities included in the advisory are:  Superior WI...Solon Springs WI...Port Wing WI...Bayfield WI...Cable WI...Ashland WI...Butternut WI...Upson WI...Hurley WI...Mercer WI...Grantsburg WI...Siren WI...Minong WI...Spooner WI...Shell Lake WI...Hayward WI...Loretta WI...Park Falls WI...Phillips WI...and Ogema WI.

*High temperatures in the upper 80s to lower 90s on Friday combined with dewpoints in the lower 70s will produce heat index values from 95 to 100 degrees Friday Afternoon and early Friday Evening.

WEATHER HEADLINES:

-Hot and muggy thru Friday away from Lake Superior
-Extreme instability but a strong cap into Friday
-If the cap breaks, look for explosive thunderstorm development
-Severe potential into Friday Evening
-4th of July weekend looks pleasant

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

The marine layer has increased around the head of Lake Superior with cold dense air trapped in place in the Superior and Duluth Harbor areas where high temperatures only made it into the 50s Today along with a copious amount of low level cloudiness.  Farther inland, skies were partly to mostly cloudy Today with southerly winds and very warm/muggy weather.  Highs were in the 80s to lower 90s with dewpoints of 65 to around 75 degrees!  Afternoon heat indices were in the mid 90s to low 100s in Western-Southern parts of our area.  Note:  At 4 PM CDT Today the heat index was 98 degrees at Hinckley, MN while at the Duluth Harbor, the temperature was just 54 degrees! Distance between Hinckley and Duluth is about 70 miles.  Winds Today were out of the south or east at 5-15 mph with some higher gusts.

Today's Upper Level Analysis:

500mb troughs covered Eastern Canada and the Pacific Northwest/Northern Rockies per water vapor satellite imagery while a large 500mb ridge was in place across the Plains and portions of the Upper Midwest.  A vigorous disturbance was lifting northeast across Utah Today and this system could be a player in our weather for Friday.  850mb temperatures as of 4 PM CDT ranged from +22 degrees C at Duluth, MN to +27 degrees C at Sioux Falls, SD to +32 degrees at Garden City, KS.  Widespread 90+ degree temperatures covered portions of the Dakotas and Minnesota, south through the Central-Southern-and Southeast U.S. Today.

Tonight:

Low pressure will be centered well to our northwest with a cold front moving into Western Minnesota Overnight.  Extreme amounts of instability will be found in our area Tonight with CAPE of 2500-5500 j/kg and Lifted Indices from -3 to -9 degrees C.  A very strong cap will likely hold most of the night, however, as 700mb temperatures range from +12 to +16 degrees C.  A few showers and thunderstorms could develop eventually, especially from late Evening through the Overnight hours mainly in Northcentral and Northeast Minnesota.  If thunderstorms develop Tonight they could turn severe due to the high amount of CAPE.  Large hail, damaging winds and dangerous lightning will be the primary risks.  Heavy rain will also be a threat with dewpoints away from Lake Superior in the 60s and 70s with PWS around 1.50".  Lows Tonight will be around 50 degrees in Superior and Downtown Duluth with 60s and 70s elsewhere.  Winds will be out of the south or east under 20 mph.

Friday and Friday Night:

A cold front will slowly move east-southeast across our area on Friday, it should exit to our east by mid or late Friday Evening the way it looks now.  A very unstable and humid airmass will be found along and ahead of the front with CAPE of 3000-5500 j/kg and Lifted Indices from -4 to -9 degrees C.  Dewpoints away from Lake Superior will be in the 60s and 70s with PWS around 1.50".  Lift associated with the cold front along with an appoaching upper level trough and a potent disturbance heading northeast from Utah should lead to a scattering of showers and thunderstorms across our area Tomorrow and Tomorrow Evening.  Severe thunderstorms are possible as well with 0-6KM and Effective Bulk Shear approaching 40 knots while mid level winds increase to 30-50 knots with an upper level jet of 70-90 knots located toward the Manitoba Lakes.  The setup for severe weather is actually quite potent for Friday and Friday Evening per 12z model run, but a cap will persist with 700mb temperatures of +12 to +14 degrees, so slightly cooler compared to Today, but it's still there.  If severe weather develops the main risks would be from large hail and damaging winds with not so much a tornado threat, although an isolated tornado risk could evolve near lake breeze boundaries or possible outflow boundaries where surface winds back.  High temperatures on Friday will be in the 80s and 90s with 50s and 60s near Lake Superior.  Lows Friday Night will be in the 50s and 60s.  Note:  Afternoon heat indices will be in the middle 90s to low 100s especially for Southern-Eastern areas.  Winds Tomorrow will be out of the north, east or south.  Winds Tomorrow Night will shift to the west or northwest.  Wind speeds during this period will range from 10-25 mph.

Extended Forecast:

Mild, but less humid conditions this weekend as high pressure builds into the Upper Midwest.  High temperatures for Saturday and Sunday will be in the 70s to lower 80s with low temperatures Saturday Night and Sunday Night in the 50s to around 60 degrees.  Cold front moves southeast into the Upper Midwest early next week, most likely Monday Night-Tuesday time frame, showers or thunderstorms could occur as that front moves through.

5 DAY FORECAST FOR DULUTH/SUPERIOR

"HEAT ADVISORY" for Superior, WI.
Timing:  12 PM Friday until 9 PM CDT Friday.

.Tonight...  Humid.  Variable cloudiness.  Showers or thunderstorms possible after Midnight.  Low 60 to 65, 50s near Lake Superior.  Wind east to southeast at 10 to 20 mph.  Chance of rain 20%.

.Friday...  Humid.  Variable cloudiness.  Showers or thunderstorms possible.  High 80 to 85 but cooler near Lake Superior.  Wind variable at 5 to 15 mph.  Chance of rain 30%.

.Friday Night...  Humid.  Variable cloudiness.  Showers or thunderstorms possible during the Evening.  Low 57 to 62.  Wind becoming west at 10 to 20 mph.  Chance of rain 30%.

.Saturday...  Less humid.  Warming up near Lake Superior.  Mostly sunny.  High 78 to 83.

.Saturday Night...  Mostly clear.  Low 55 to 60.

.Sunday...  Partly cloudy.  High 75 to 80.

.Sunday Night...  Mostly clear.  Low 55 to 60.

.4th of July...  Partly cloudy.  High 75 to 80.

Normal temperatures for Today

High:  74 degrees
Low:  52 degrees

Friday's Pollen Forecast:

Grass:  Moderate
Tree:    Low
Weed:  None

Sunrise Tomorrow:  5:18 AM CDT
Sunset Tomorrow:   9:07 PM CDT

Tim